code: def interact(
      model: Chainer, payload: Dict[str, Optional[List]]
  ) -> List:
      model_args = payload.values()
      dialog_logger.log_in(payload)
      error_msg = None
      lengths = {
          len(model_arg)
          for model_arg in model_args
          if model_arg is not None
      }
  
      if not lengths:
          error_msg = "got empty request"
      elif 0 in lengths:
          error_msg = "got empty array as model argument"
      elif len(lengths) > 1:
          error_msg = "got several different batch sizes"
  
      if error_msg is not None:
          log.error(error_msg)
          raise HTTPException(status_code=400, detail=error_msg)
  
      batch_size = next(iter(lengths))
      model_args = [arg or [None] * batch_size for arg in model_args]
  
      prediction = model(*model_args)
  
      # TODO: remove in 1.2.0
      if COMPATIBILITY_MODE is not False:
          if len(model.out_params) == 1:
              prediction = [prediction]
          prediction = list(zip(*prediction))
  
      result = jsonify_data(prediction)
      dialog_logger.log_out(result)
      return result
  
imports: import asyncio
  import os
  from collections import namedtuple
  from logging import getLogger
  from pathlib import Path
  from ssl import PROTOCOL_TLSv1_2
  from typing import Dict, List, Optional, Union
  import uvicorn
  from fastapi import Body, FastAPI, HTTPException
  from fastapi.utils import generate_operation_id_for_path
  from pydantic import BaseConfig, BaseModel
  from pydantic.fields import Field, ModelField
  from pydantic.main import ModelMetaclass
  from starlette.middleware.cors import CORSMiddleware
  from starlette.responses import RedirectResponse
  from deeppavlov.core.commands.infer import build_model
  from deeppavlov.core.commands.utils import parse_config
  from deeppavlov.core.common.chainer import Chainer
  from deeppavlov.core.common.file import read_json
  from deeppavlov.core.common.log import log_config
  from deeppavlov.core.common.paths import get_settings_path
  from deeppavlov.core.data.utils import check_nested_dict_keys, jsonify_data
  from deeppavlov.utils.connector import DialogLogger
  from deeppavlov.utils.server.metrics import metrics, PrometheusMiddleware
label_desc: Use image node_id 4 for calling a global function with example usage: interact(model, payload) and returns: result